Question: Complete the recursive formula of the geometric sequence $-0.3\,,\,0.9\,,-2.7\,,\,8.1,...$. $b(1)=$
The first term is $-0.3$ and the common ratio is $-3$. ${\times (-3)\,\curvearrowright}$ ${\times (-3)\,\curvearrowright}$ ${\times (-3)\,\curvearrowright}$ $-0.3,$ $0.9,$ $-2.7,$ $8.1,...$ This is the recursive formula of $-0.3\,,\,0.9\,,-2.7\,,\,8.1,...$. $\begin{cases} b(1)=-0.3 \\\\ b(n)=b(n-1)\cdot(-3) \end{cases}$